AP Stats Stats: Evaluation Overview 2

Question 1

A researcher wants to test whether a new drug reduces blood pressure. Which type of study provides the strongest evidence of causation?

Accepted Answer

Randomized controlled experiment

Answer

Randomized controlled experiments allow causal conclusions because random assignment controls for confounding variables.

Question 2

In hypothesis testing, the p-value represents:

Accepted Answer

The probability of observing results at least as extreme as the sample, assuming H₀ is true

Answer

The p-value is the probability of obtaining a test statistic as extreme or more extreme than observed, given H₀ is true.

Question 3

A 95% confidence interval for a population mean is (12.4, 18.6). Which interpretation is correct?

Accepted Answer

If we repeated sampling many times, about 95% of such intervals would contain the true mean

Answer

Confidence level refers to the long-run proportion of intervals constructed this way that capture the true parameter.

Question 4

Which of the following is an example of a Type I error?

Accepted Answer

Rejecting a true null hypothesis

Answer

A Type I error (false positive) occurs when we reject H₀ even though it is actually true.

Question 5

A scatterplot shows a strong negative linear association between two variables. The correlation coefficient r is most likely:

Accepted Answer

-0.92

Answer

A strong negative linear association corresponds to r close to -1, making -0.92 the best choice.

AP Practice Test